System, method, and apparatus for providing auxiliary power, heating, and air conditioning for a vehicle

ABSTRACT

An auxiliary system provide auxiliary power and air conditioning for a vehicle while a main engine of the vehicle is not operating. An auxiliary alternator is mounted to and driven directly by the drive shaft of an auxiliary engine. The auxiliary alternator has permanent magnets and three sets of windings, including two sets of windings for generating AC voltage via inverters, and a second set of windings for generating DC voltage for directly recharging a battery of the vehicle via a regulator. An air conditioner compressor also is driven by the auxiliary engine for compressing refrigerant. A condenser is in fluid communication with the compressor for condensing the refrigerant, an evaporator is in fluid communication with the refrigerant condensed by the condenser, and an electric blower moves air through the evaporator into the interior of the vehicle.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates in general to auxiliary power systems for vehicles and, in particular, to an improved system, method, and apparatus for providing auxiliary power, heating, and air conditioning for a vehicle.

2. Description of the Related Art

Many vehicles are equipped with air conditioning and heating systems. The vehicle's engine drives a compressor that compresses refrigerant and delivers it to a condenser. The condenser converts the hot gaseous refrigerant to a liquid refrigerant. The liquid refrigerant flows to an evaporator where it undergoes a pressure drop, converting the liquid refrigerant to a cold gas. An interior blower moves air through the evaporator and into the interior of the vehicle. The condenser is cooled by the main engine fan, which also flows air through the engine radiator. For heating, a heater coil or element is mounted in the vehicle, typically in communication with the radiator via hoses. A portion of the hot engine coolant flows through the heater element, and the interior blower moves air through the heater coil to heat the interior of the vehicle.

Many large vehicles, such as tractor trailer trucks, recreational vehicles, house trailers, etc., have sleeping compartments attached to or part of the interior for allowing the driver or passengers to rest. Some vehicles have separate or rear units for heating and cooling the sleeping compartment. The rear unit typically comprises an evaporator in parallel with a main evaporator, and a heater element in parallel with the main heater element. The rear unit uses the same compressor and condenser as the main unit. In order for the rear unit to operate, the operator must run the main engine of the vehicle. These vehicles are often parked while running the rear unit. Unfortunately, the main engine generates far more power at idle than is needed for operating the rear unit, resulting in a wasted fuel.

One approach for heating and cooling a sleeping compartment while a vehicle is parked is to utilize a 110 volt air conditioning unit on the vehicle. Some rest stops have service receptacles that enable the operator to connect a power cord to the 110 volt air conditioning unit. Many rest stops, however, do not have such provisions for connecting a vehicle to AC (alternating current) electrical power.

Also, in the prior art, portable generators have been mounted to some vehicles for generating 110-115 volt AC power. An auxiliary engine, normally diesel, is located in a compartment along with an AC generator. The generator powers a 110 volt air conditioning unit mounted to the sleeping compartment. The air conditioning unit has an AC electrical motor that drives the compressor and the fan. For heat, an electrical resistance element is employed. These systems are normally referred to as “gen-sets.”

Another prior art approach, sometimes referred to as an “auxiliary power unit,” utilizes an auxiliary engine in an external compartment on a vehicle to directly drive a motor vehicle-type compressor. Typically, a condenser and radiator are located in the external compartment. An evaporator, heater element, and DC (direct current) blower are mounted within the sleeping compartment. The compressor delivers refrigerant to the condenser, which in turn delivers condensed refrigerant to the evaporator for cooling the interior of the vehicle. For heating, a portion of the coolant from the auxiliary engine may be diverted from the radiator to the heater element. In one such system, when the heater is turned on, a valve assembly proportionately reduces the coolant flowing to the auxiliary radiator while increasing the coolant flowing to the heater element.

Prior art auxiliary power units do not have generators. Rather, they have alternators that supplies DC (direct current) voltage. The DC voltage powers the blower for the evaporator and heater element and drives the fan for the condenser and radiator. The alternator of the auxiliary unit also charges the main batteries of the vehicle. This type of unit may also have an inverter that converts part of the DC voltage from the auxiliary engine alternator into AC voltage for running AC appliances in the sleeping compartment. Although each of these prior art designs are workable, an improved solution would be desirable.

SUMMARY OF THE INVENTION

One embodiment of a system, method, and apparatus for providing auxiliary power to a vehicle while a main engine of the vehicle is not operating is disclosed. The invention comprises an auxiliary engine having a drive shaft. An auxiliary alternator is mounted to and driven directly by the drive shaft of the auxiliary engine. The auxiliary alternator has permanent magnets and at least two sets of windings, including a first set of windings for generating AC voltage via an inverter to provide auxiliary power to the vehicle, and a second set of windings for generating DC voltage to recharge a battery of the vehicle. A regulator regulates the output of DC voltage from the second set of windings to, for example, directly recharge the battery while the main engine of the vehicle is not operating. The DC voltage also may be used to power other electrical components.

In one embodiment, the first set of windings comprises two sets of windings and the inverter comprises two inverters. Depending on the application, each of the inverters may produce about 2.5 to 3 kW at approximately 115 to 120 volts AC. The regulator may produce approximately 12 to 14 volts DC at about 60 amps. In addition, an air conditioner compressor may be mounted to and driven by the auxiliary engine for compressing refrigerant, with a condenser in fluid communication with the compressor for condensing the refrigerant, an evaporator in fluid communication with the refrigerant condensed by the condenser, and an electrically driven blower mounted adjacent the evaporator for moving air through the evaporator and into an interior of the vehicle.

The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.

FIG. 1 is a schematic elevational view of a vehicle having an auxiliary power system constructed in accordance with the present invention;

FIG. 2 is a simplified electrical diagram of the auxiliary power system of FIG. 1 and is constructed in accordance with the present invention; and

FIG. 3 is a high level flow diagram of one embodiment of a method constructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a vehicle 11, such as a recreational vehicle, truck, etc., has an engine compartment 13, a cab 15 and, optionally, a sleeping compartment 17. For simplicity, a truck 11 is illustrated. The interior of sleeping compartment 17 may be in common with the interior of cab 15. An auxiliary power source 19 is shown mounted to a frame 21 of truck 11. Auxiliary power source 19 may be located in various positions on truck 11, and is typically rearward of sleeping compartment 17. Auxiliary power source 19 may be located within a housing or exterior compartment 23. An auxiliary evaporator and heater unit 25 is preferably located separate from compartment 23. In one embodiment, evaporator and heater unit 25 is located within sleeper compartment 17, preferably on the floor under a bed or bunk.

Truck 11 has a primary or main engine 27, normally diesel, that propels truck 11. Hoses connect a main radiator 29 to main engine 27 for receiving engine coolant. An engine fan 30 is directly driven by main engine 27 for causing air flow through main radiator 29. Truck 11 also has a main interior heater element or coil 31 and a main interior blower 33. Heater element 31 is connected by hoses to radiator 29 for receiving a portion of the flow of engine coolant. Blower 33 moves air through heater element 31 for heating the interior of cab 15. Valves (not shown) controlled by the driver will selectively provide or stop the flow of engine coolant through heater 31.

For cooling, main engine 27 drives a main compressor 35 by a belt (not shown). Compressor 35 delivers hot gaseous refrigerant to a main condenser 37 that is mounted parallel to radiator 29. Condenser 37 condenses the refrigerant to a liquid, which flows to a main evaporator 39. Typically, the same interior blower 33 moves air through evaporator 39 into the interior of cab 15.

In some cases, sleeper compartment 17 is provided with a rear evaporator, heater element, and blower (not shown) for heating and cooling sleeper compartment 17. If so, main compressor 35 and main condenser 37 supply refrigerant to the rear evaporator. Main engine 27 and radiator 29 may supply coolant to the rear heater element for heating. Main engine 27 also has a main alternator 41 driven by a belt. Alternator 41 supplies DC electrical power for blower 33 and other uses. Alternator 41 also charges a main battery 43 or set of batteries.

Auxiliary power source 19 includes an auxiliary engine 45 which, in one embodiment, may comprise a small water-cooled diesel engine. Auxiliary engine 45 has fluid lines connected to a radiator 47 that is also mounted in compartment 23. Auxiliary engine 45 drives an alternating current alternator 49 that supplies 115 volts of AC voltage. Auxiliary engine also provides DC voltage via a regulator 53. Regulator 53 may comprise a high amp, 14V regulator, and is directly connected to the main truck battery 43 for maintaining battery 43 at full charge while auxiliary power source 19 is operating. AC alternator 49 is also connected to one or more AC outlets in sleeper compartment 17 for providing AC electrical power, such as for powering AC appliances and the like.

An optional auxiliary compressor 57 is mounted to and driven by auxiliary engine 45. Auxiliary compressor 57 may comprise a conventional motor vehicle air conditioner compressor. Auxiliary compressor 57 is connected by a hose to an auxiliary condenser 59, which is also located in exterior compartment 23. Auxiliary condenser 59 may be located in parallel to and upstream from radiator 47. A single fan 61 moves air through condenser 59 and radiator 47. Fan 61 may be powered by, e.g., either power source described above.

Evaporator and heater unit 25 is also preferably located under the bunk or bed within compartment 17, but it could be mounted to the exterior back wall of sleeping compartment 17. Evaporator and heater unit 25 includes an evaporator 65 that receives condensed refrigerant from condenser 59. A heater element 67 is mounted next to evaporator 65. Heater element 67 could be of a type that utilizes electrical resistance, but preferably is one that is connected to auxiliary radiator 47 for circulating coolant. A single blower 69 moves air through evaporator 65 and heater element 67. Blower 69 may utilize a DC motor connected to the DC output of regulator 53 but, alternately, it may utilize an AC motor. In one embodiment, auxiliary engine 45 and alternator 49 are mounted next to each other on a common support frame. In another embodiment, a single drive shaft may be used to directly drive alternator 49 and indirectly drive compressor 57 via a belt.

The evaporator and heater unit 25 may include a housing that houses evaporator 65 and heater element 67, with the blower 69 mounting to the housing. The housing may include outlet ports for discharging air heated or cooled by evaporator 65 or heater element 67. The outlet ports may be connected to ducts that lead to registers placed at desired points within sleeping compartment 17.

Referring now to FIG. 2, one embodiment of a simplified schematic diagram for a system for providing auxiliary power to a vehicle while the main engine of the vehicle is not operating is shown. As described above, the system comprises auxiliary engine 45 having a drive shaft for directly driving the auxiliary alternator 49. The auxiliary alternator 49 has permanent magnets and at least two sets of windings, including a first set of windings 101 (e.g., two shown) for generating AC voltage via one or more inverters 103 (e.g., two shown) to provide auxiliary power. A second set of windings 105 is used to generate DC voltage to recharge a battery (e.g., main battery 43) of the vehicle 11. The regulator 53 regulates the output of the DC voltage from the second set of windings 105 to directly recharge the battery 43 while the main engine 27 of the vehicle 17 is not operating. In one embodiment, each of the inverters 103 produces about 2.5 to 3 kW at approximately 115 to 120 volts AC at 60 Hz in perfect sine wave form, and the regulator 53 produces approximately 12 to 14 volts DC at about 60 amps, and, for example, up to about 200 amps.

In operation, there is no need to operate auxiliary power source 19 while main engine 27 is operating. Main engine 27 supplies sufficient power for heating and cooling while it is in operation. When truck 11 has stopped for an extended period, the operator may stop engine 27 and turn on auxiliary engine 45. Battery 43 provides voltage to a starter (not shown) of auxiliary engine 45.

Auxiliary engine 45 drives alternator 49 to generate 115 AC volt power. Alternator 49 also provides power to regulator 53, which regulates the DC voltage to battery 43, and provides power for other electrical devices or applications 109, such as, e.g., trailer lights, vehicle accessories, other electrical components, etc. Some of the AC voltage is also supplied through outlets in the interior of sleeping compartment 17 for electrical devices like AC appliances 107, such as, e.g., a television, microwave, stereo, computer, tools, etc.

If cooling is desired, a clutch (not shown) for auxiliary compressor 57 engages compressor 57, causing it to supply pressurized refrigerant to condenser 59. Condenser 59 delivers condensed refrigerant to evaporator 65. A pressure drop causes the refrigerant to expand, and blower 69 moves air across evaporator 65 into the interior of sleeping compartment 17. The refrigerant returns from evaporator 65 to compressor 57. If heat is desired in compartment 17, compressor 57 is disengaged and blower 69 causes air movement through heater element 67 into the interior of sleeper compartment 17.

Referring now to FIG. 3, one embodiment of a method of providing auxiliary power to a vehicle while a main engine of the vehicle is not operating. The method begins as indicated at step 301, and may comprise providing an auxiliary engine having a drive shaft, and an auxiliary alternator having permanent magnets and at least two sets of windings (step 303); driving the auxiliary alternator directly with the drive shaft of the auxiliary engine (step 305); generating AC voltage with a first set of windings of the auxiliary alternator via an inverter to provide auxiliary power (step 307); generating DC voltage with a second set of windings of the auxiliary alternator (step 309); regulating an output of the DC voltage from the second set of windings to directly recharge the battery while the main engine of the vehicle is not operating (step 311); before ending as indicated at step 313.

The method may further comprise driving an air conditioner compressor with the auxiliary engine for compressing refrigerant; condensing the refrigerant with a condenser that is in fluid communication with the compressor; evaporating the refrigerant condensed by the condenser with an evaporator; and moving air through the evaporator and into an interior of the vehicle with an electrically driven blower mounted adjacent the evaporator. In addition, the method may further comprise providing power to additional electrical devices.

The present invention has several advantages including the ability to regulate at least a portion of the output of an auxiliary power source, rather than the regulating the input. The regulated output may be used to directly recharge the main battery of a vehicle when the main engine of the vehicle is not operating. Moreover, the invention does not require the use of an alternator or battery charger to accomplish this advantage. The additional winding used to perform this function adds additional density to the rotor to increase its mechanical operational capacity as a flywheel which, in turn, produces smoother, quieter power for the end user at lower auxiliary engine speeds. Consequently, this design has lower emissions to reduce its environmental impact during operation.

While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. 

1. A system for providing auxiliary power to a vehicle while a main engine of the vehicle is not operating, comprising: an auxiliary engine having a drive shaft; an auxiliary alternator mounted to and driven directly by the drive shaft of the auxiliary engine, the auxiliary alternator having permanent magnets and at least two sets of windings, including a first set of windings for generating AC voltage via an inverter to provide auxiliary power, and a second set of windings for generating DC voltage to recharge a battery of the vehicle; and a regulator for regulating an output of the DC voltage from the second set of windings to directly recharge the battery while the main engine of the vehicle is not operating.
 2. A system according to claim 1, wherein the first set of windings comprises two sets of windings and the inverter comprises two inverters, with each of the inverters producing about 2.5 to 3 kW at approximately 115 to 120 volts AC, and the regulator produces approximately 12 to 14 volts DC at about 60 amps.
 3. A system according to claim 1, further comprising: an air conditioner compressor mounted to and driven by the auxiliary engine for compressing refrigerant; a condenser in fluid communication with the compressor for condensing the refrigerant; an evaporator in fluid communication with the refrigerant condensed by the condenser; and an electrically driven blower mounted adjacent the evaporator for moving air through the evaporator and into an interior of the vehicle.
 4. A vehicle, comprising: a main engine and a main battery; an external auxiliary compartment connected to an exterior of the vehicle; an auxiliary system positioned in the external auxiliary compartment, the auxiliary system comprising: an auxiliary engine having a drive shaft; an auxiliary alternator mounted to and driven directly by the drive shaft of the auxiliary engine, the auxiliary alternator having permanent magnets and at least two sets of windings, including a first set of windings for generating AC voltage via an inverter to provide auxiliary power, and a second set of windings for generating DC voltage to recharge a battery of the vehicle; and a regulator for regulating an output of the DC voltage from the second set of windings to directly recharge the battery while the main engine of the vehicle is not operating.
 5. A vehicle according to claim 4, wherein the first set of windings comprises two sets of windings and the inverter comprises two inverters, with each of the inverters producing about 2.5 to 3 kW at approximately 115 to 120 volts AC, and the regulator produces approximately 12 to 14 volts DC at about 60 amps.
 6. A vehicle according to claim 4, further comprising: an air conditioner compressor mounted to and driven by the auxiliary engine for compressing refrigerant; a condenser in fluid communication with the compressor for condensing the refrigerant; an evaporator in fluid communication with the refrigerant condensed by the condenser; and an electrically driven blower mounted adjacent the evaporator for moving air through the evaporator and into an interior of the vehicle.
 7. A method of providing auxiliary power to a vehicle while a main engine of the vehicle is not operating, the method comprising: (a) providing an auxiliary engine having a drive shaft, and an auxiliary alternator having permanent magnets and at least two sets of windings; (b) driving the auxiliary alternator directly with the drive shaft of the auxiliary engine; (c) generating AC voltage with a first set of windings of the auxiliary alternator via an inverter to provide auxiliary power; (d) generating DC voltage with a second set of windings of the auxiliary alternator; and (e) regulating an output of the DC voltage from the second set of windings to directly recharge the battery while the main engine of the vehicle is not operating.
 8. A method according to claim 7, wherein the first set of windings comprises two sets of windings and the inverter comprises two inverters, with each of the inverters producing about 2.5 to 3 kW at approximately 115 to 120 volts AC, and the regulator producing approximately 12 to 14 volts DC at about 60 amps.
 9. A method according to claim 7, further comprising: driving an air conditioner compressor with the auxiliary engine for compressing refrigerant; condensing the refrigerant with a condenser that is in fluid communication with the compressor; evaporating the refrigerant condensed by the condenser with an evaporator; and moving air through the evaporator and into an interior of the vehicle with an electrically driven blower mounted adjacent the evaporator.
 10. A method according to claim 7, wherein step (e) further comprises providing power to additional electrical devices. 